Synopsis
Identify secondary and obstructive constipation, recognise overflow from rectal loading, relieve impaction safely, and build a sustainable bowel regimen with specialist testing reserved for refractory defined phenotypes.
- Constipation is not only infrequent stool: ask about hard form, straining, incomplete evacuation, blockage sensation, manual manoeuvres, pain and the patient's baseline.
- New constipation with rectal bleeding, iron-deficiency anaemia, weight loss, abdominal or rectal mass, or persistent change in bowel habit needs the current colorectal cancer pathway.
- Faecal impaction can present with overflow liquid stool, faecal incontinence, urinary retention, anorexia, delirium or apparent diarrhoea, particularly in frailty and neurological disease.
- Review opioids, anticholinergics, iron, calcium, verapamil, antipsychotics and anti-Parkinson medicines, and assess hydration, mobility, toileting privacy and access.
- Digital rectal examination should answer whether rectal stool, mass, bleeding or evacuation dysfunction is present; a loaded proximal colon can coexist with an empty rectum.
- Exclude obstruction before escalating oral laxatives. A plain abdominal radiograph is not routinely required for uncomplicated constipation but can help selected acute or uncertain cases.
- For routine chronic constipation, adequate soluble fibre and fluid, regular toileting and an osmotic laxative are common first steps; stimulant treatment is added or substituted according to stool response.
- Impaction needs a disimpaction regimen followed immediately by maintenance treatment and correction of the cause, otherwise rapid recurrence is predictable.
- Symptoms of outlet obstruction despite soft stool may need anorectal physiology and pelvic-floor biofeedback rather than simply stronger laxatives.
Key red flags
Progressive distension, colicky then constant pain, vomiting, absolute constipation, weight loss or a mass raises tumour, volvulus or stricture. Peritonism, fever or shock suggests ischaemia or perforation and precludes routine laxative escalation.
New constipation or retention with saddle sensory change, severe back pain, bilateral weakness, altered anal tone or urinary dysfunction raises cauda equina or spinal compression and requires emergency neurological imaging and referral.
Investigation priorities
Detect distal stool, rectal mass, blood, anal tone and a possible evacuation coordination problem.
Management branches
Constipation is new, severe or associated with pain, vomiting, distension or urinary symptoms.
- Assess physiology, hydration, abdomen, hernias and stool or flatus passage, and ask about cancer, postoperative and medicine risks.
- Seek peritonism, absolute obstipation and neurological warning features, performing rectal and focused lower-limb examination when clinically indicated.
- Escalate suspected mechanical obstruction or cauda equina urgently and avoid oral disimpaction until the dangerous mechanism is excluded.
- Use imaging and blood tests to answer the specific obstruction, perforation, metabolic or neurological question with senior input.